The purpose of the study was to establish the influence of staff discipline on school performance in primary schools in Lugusuulu Sub-County, Sembabule District, Uganda. The study was guided by three objectives which are to find out the extent to which teacher’s personal conduct affects the performance of primary school in Lugusuulu Sub-County, Sembabule District, Uganda, to assess the relationship between teachers’ professional responsibility and the performance of primary schools and to establish how the teachers’ relationship with learners affect the performance of primary schools. The researcher used questionnaires and interview schedules as major instruments of data collection. The researcher used a cross sectional research design where both qualitative and quantitative research methods were used. Questionnaire and interview guides were used to gather information from the respondents. A total of one hundred and one forty (140) respondents were used as a sample from the ten selected schools in Lugusuulu Sub-County, Sembabule District, Uganda. Reliability of the questionnaire was established with the use of test-retest reliability with a value of 0.74 and validity was determined through face and content validity with a CVI value of 0.78. Data were analyzed using table, figures, frequencies and percentages. Pearson correlation coefficient was also utilized in this study to determine relationship between the variables. This study found that there was a relationship between teachers’ professional responsibility and the performance of primary schools in Lugusuulu Sub-County, Sembabule District, Uganda primary Schools in Sembabule District. The key findings of this study are that, teachers’ personal conduct professional responsibility and personal relationship with learners has a significant relationship with school performance of primary schools in Bugokho Sub County. This study made the following recommendations; teachers to handle well pupils and play their part as expected, including managing time, syllabus completion emphasis on procedures and management practices. Monitoring and evaluation of teachers’ activities in primary schools need to be emphasized to ensure that all teachers obey the government regulations concerning education.